Question

if the solar declination is 23.5 deg and latitude angle is 45 deg , then the sunrise hour angle is

Answer 1

The sunrise equation is :  Cos ω₀ = - tan ∅ × tan α  Where :  ω₀ = hour angle at sunrise   ∅ = latitude of the observer on earth  α = sun declination  Doing the substitution we have :​  Cos ω₀ = - Tan 45 × Tan 23.5  Cos ω₀ = - 1 × 0.4348  = - 0.4348  Cos ⁻¹ (-0.4348) = 115.77°  ω₀ = 115.77°